Nature did it



Methane hydrate, the fire ice/Wikimedia commons

News analysis


The Ice Age ended almost 12,000 years ago, and yet – if  a team of German and Norwegian scientists are to be believed – it continues to influence earth’s climate to this day.

The scientists have concluded that methane seeps off Svalbard Island, a remote chunk of Arctic real estate about halfway between the country of Norway and the North Pole, are due not to human-caused global warming as had first been suspected, but instead are linked to changes in the planet’s surface that date back to the retreat of the ancient ice.

The scientist said that what is going on off Svalbard is a reaction to the weight of hundreds of tons of ice melting. As the pressure on the northern landscape has decreased, the land and the seabed have risen. As the seabed rose, there was less water pressure on methane hydrates on the ocean bed, and they began to break up.

Methane hydrates are a potential energy source. You can think of them as fire-ice. In their solid state, they will burn like lumps of coal –  only cleaner. 

They are also a potential environmental nightmare. As they break down naturally, they become largely water and methane, a natural gas, which promptly floats off into the atmosphere.

Methane is a greenhouse gas far more powerful than carbon dioxide (CO2) over the short-term. As decades pass, it decays into CO2. But in the first 20 years before that happens, the Intergovernmental Panel on Climate Change estimates it is 84 times more powerful at warming the planet than CO2.

“Vast amounts of methane are bound in gas hydrates that accumulate in seafloor sediments across continental margins,” Klaus Wallman and associates wrote in their paper published in Nature Communications last month. “These ice-like solids are stable under high pressure/ low temperature conditions but dissociate under ocean warming or relative sea-level lowering. The global gas hydrate inventory totals some 1000 billion metric tons of carbon, the decomposition of which would affect carbon cycling and climate on the global scale.”

This is the polite, scientific way of saying methane hydrates could further accelerate global warming. There have been ever rising concerns expressed about Arctic methane as the planet has warmed in recent years.

“Seven facts you need to know about the Arctic methane timebomb,” The Guardian put it in a chilling, or would that be explosive, headline five years ago. 

Number two on the list compiled by Nafeez Ahmed, executive director of the Institute for Policy Research & Development,  was this:

“Arctic methane hydrates are becoming increasingly unstable in the context of anthropogenic climate change and it’s impact on diminishing sea ice.”

“Anthropogenic” is the fancy word for “human caused.”

We bad

Humans are the easy target for every uptick in temperature in the on-going climate change discussion because humans – like most animals – largely live for the here-and-now and maybe tomorrow.

Beyond that, some people might choose to contemplate, but few are moved to action, especially if it means sacrificing today for some nebulous return far over the horizon.

Yes, as good citizens of planet earth each of us should be using a shovel to clear the driveway to avoid calling the  plow company with its hydrocarbon-burning truck that adds to global CO2, or firing up the less-than-efficient snowblower that burns gas that contributes to global CO2.

But shoveling is hard work. So we look for easier alternatives. This is in the nature of every animal on the planet. And because we, as humans, are big on our own self-importance, it is easy for us to conclude that everything – bad or, occasionally, good – revolves around us.

What the scientists found off Svalbard is that it doesn’t.

How this all plays into the big and complicated question of climate change no one really knows. It is impossible to argue that humans have no influence, given the apparent link between the rise of the Industrial Revolution with its CO2-spewing machinery, and the corresponding increase in atmospheric CO2. 

But the Svalbard study would indicate that climate is not quite as simple as we’d sometimes like to believe.

“Svalbard shows limited influence from short-term ocean warming,” the scientists reported, with the big influence being “post-glacial isostatic rebound.”

An Alaska problem

Alaskans should be well aware of post-glacial land changes. Long ago, isostatic rebound became the subject of an Alaska lawsuit that went all the way to the state Supreme Court. The case involved 117 acres of land near Juneau that was state-owned tidelands until it wasn’t.

With the Mendenhall Glacier in retreat, the land rebounded and became uplands instead of tidelands. An adjacent homesteader promptly claimed the land as part of his homestead.

He and the state ended up in court where the state won title to the rebounding property, although the court noted “the appellants’ situation is compelling. (Daniel) Pederson and the appellants obviously believed they owned down to the shoreline. They have used the property as shorefront property and have exercised the incidents of ownership over the accreted land for the last 50 years. Unfortunately, the evidence seems clear that both the 1932 and the 1924 surveys did not convey to a meander line, and the surveys must control.”

Since then, rebounding lands have  been the subject of other lawsuits and a considerable amount of study.  The studies would indicate that even as Alaska is worrying about climate-linked coastal flooding in some areas, land is rising out of the flood zone in other locations.

Not that the picture is all roses.  One study concluded the decreasing pressure of water on the sea floor could increase the chances of volcanic eruptions. 

But that might be a small problem compared to what the scientists are seeing with methane hydrates in the Arctic these days. Due to slow, geologic-time rebound from glacial retreat and with a little help from global warming, the scientists say, it would appear a solid layer of methane hydrates that once sealed in vast volumes of methane below is breaking up.

“Our data and model results also show that gas hydrates are not in themselves a significant source for gas release at the seabed,” they wrote. “Rather, they act as a dynamic seal that blocks fluid-flow pathways for gas migration from deep geological reservoirs. Previous estimates of seafloor methane emissions by ongoing and future gas hydrate decomposition consider gas released from hydrates but ignore the potentially more significant increase in flux from underlying gas reservoirs upon hydrate dissociation. Hence, the impact of future seabed methane fluxes on global environmental change may yet be underestimated.”

That flux, of course, has the potential to accelerate global warming, meaning Alaska might yet become that place to be The New York Times predicted in 2014. 

















4 replies »

  1. Craig,
    You make an excellent argument to switch to renewable energy sources over time since “fracking” for gas only dumps more Methane into our air…something our state officals fail to speak of.

    • Completely misses the point. The amount we release is inconsequential to natural release, and “renewables” are not up to the task in the real world given economic and logistical realities. Unless of course you mean modern nuclear power?

      • Matthew,

        Maybe you should read the link I reference…
        A 30 Percent increase in Methane since 2002 is very consequential to our environment.
        As for “Renewables”…well they have been proven to work fine….unlike your nuclear power suggestion that blew up in Chernobyl and Japan.

        “While this new study doesn’t attribute a specific source to the remarkable 30 percent increase in U.S. methane emissions from 2002–2014, many other studies have identified the source of those emissions as leakage of methane from the natural gas production and delivery system.”

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